Whisk in the water, followed by the red gel, purple gel, and corn syrup.
Add any more color if necessary. To make it thicker, add a little bit of cornstarch or cocoa powder.To make it more opaque, add more cornstarch.Too thick, add a little bit of water.
The fake edible blood should be smooth in texture and have the viscosity of maple syrup, chocolate for a drip cake.